


System Glitch

by Mylz



Category: Undertale (Video Game), 僕のヒーローアカデミア | Boku no Hero Academia | My Hero Academia
Genre: Angry Bakugou Katsuki, Asexual Midoriya Izuku, Bakugou Katsuki is Bad at Feelings, Crazy Toga Himiko, Cute Midoriya Izuku, Dabi is Bad at Feelings (My Hero Academia), Dabi is Todoroki Touya, Dabi is a Little Shit (My Hero Academia), Doctor Midoriya Izuku, Gen, Izuku Midoriya is W.D. Gaster, Jealous Bakugou Katsuki, Midoriya Izuku Has a Quirk, Midoriya Izuku Needs A Hug, Multi, One-sided Midoriya Izuku/Toga Himiko, Sassy Midoriya Izuku, Scientist Midoriya Izuku, Scientist W. D. Gaster, Sweet Toga Himiko, The Core (Undertale), Toga Himiko is Not a Villain, Toga Himiko is a Good Friend, Vigilante Dabi (My Hero Academia), Vigilante Midoriya Izuku, Vigilante Toga Himiko
Language: English
Status: In-Progress
Published: 2020-12-13
Updated: 2020-12-13
Packaged: 2021-03-10 19:35:20
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings, Graphic Depictions Of Violence, No Archive Warnings Apply
Chapters: 1
Words: 2,403
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28042512
Author URL: https://archiveofourown.org/users/Mylz/pseuds/Mylz
Summary: Izuku Midoriya was a normal boy, the only difference he had from others, was a small golden heart he had whenever he concentrated hard enough. he was the only one with a golden heart. his friend turned to bully for 1 year had a red heart, his teacher had a blue heart, and so on.Izuku Midoriya wanted to be a hero, so when he finds a dying Skeletor man in the jungle with a breaking apart golden heart, Izumi saves him. that night, Izuku didn't know he saved the number 1 hero.that night, Izuku learned why had he never seen someone without a small heart, becausethisis what they turned into.
Relationships: Dabi & Midoriya Izuku & Toga Himiko, No Romantic Relationship(s), yet
Comments: 4
Kudos: 41





	System Glitch

**Author's Note:**

  * Inspired by [My Hero Glitchtale](https://archiveofourown.org/works/27987153) by [EbayUserGreen](https://archiveofourown.org/users/EbayUserGreen/pseuds/EbayUserGreen). 



> I read this Ghaster Izuku fic and found it inspiring so here we are.  
> Also for Izuku's personality, I went for a merge of Glitch tale Ghaster x Alstor (Hazbin Hotel) x Doofenstine. but not as dumb as him, as his sense of comedy resembles the man from Finease and Ferb.

All Might slowly limp out of the battlefield, _**He** _was dead, his master was avenged, even if he was bleeding out, it was fine, his only sadness was OFA, he couldn't get the idea of such a heroic power go to waste, he fell to his knees, and finally his vision went dark.

Izuku was having nightmares, they felt too real for him to ignore, In the distance, he saw two of the brightest hearts he had seen. one was just like his; a majestic golden in color and pure in essence, but the other, a living nightmare stood no chance against it. as he got closer to the scene, the brightness of both hearts dimmed, turning almost transparent, Izumi ignored the dark one and ran towards the bright one, he saw it. a man, looking more like a skeleton, was walking slowly away from the field. His feet were wobbly and not a moment later he fell on his knees. Izuku rushed to the man's side, he thought of what to do, or how to do it, when he saw it, what happened whenever someone was dying, the heart started to dissipate, Izuku didn't want to be the useless Deku Bakugo said he was, he **needed** to save this man, and so, he made the most drastic measure in his life.

Izuku always felt the tug at his heart when other people hearts dissipated, after he did it once, he found out why. his quirk, dubbed by the doctor 'The Seer' allowed him to take the soul of dying people, the later he did it, the smaller the soul he got, so in a desperate attempt, Izuku sucked in the golden soul of the man and gave him his own full soul, the change was instantaneous. The man grew in muscle, getting bulkier and bigger until all there was left was a buff man who looked too similar to All Might. Izuku would have noticed the similarities if he wasn't doubling down in pain. His skin burned brighter than the sun, melting off of his body. He lost all of his hair and was left with a white exoskeleton with two massive cracks from his eye sockets, his eyes melted off and were replaced with hallow holes he could light up with a small fire to act as iris. His hands were indented as he watched in horror how a hole formed in them, He also noticed the Heart he took had placed itself calmly in his chest, Looking at it, it was not even a full 1/4 of a heart. He lifted his face and ran.

when he reached a river, he screamed, because the abomination that looked back wasn't him right? If no one liked him before, now they would call him a villain, and Izuku Midoriay, 5 years old, didn't like being called a villain. he ran, from Musufatu, from Tokyo, and for a while from Japan. even he didn't know where he went back then, but when the time comes, He will be back, Izuku [Gaster] Midoriya, wasn't gonna sit back and let unjust evil get what it wants because as long as there was just evil like him, petty criminals had no other choice but to surrender.

* * *

All Might wake up confused, after he killed AFO, he dropped to his knees and blacked out. he couldn't remember much, but he felt something like his whole being was sucked out of him and then something else filled it, it was bright, it was filled with energy and it saved him. suddenly the whole in his stomach started filling itself, suddenly the lung he lost started to repair itself, he was almost about to go back to unconsciousness when he caught a glimpse of his savior, that face, that form, that thing was all wrong. his savior looked like a kid, in pain, his hair fell and his skin melted off his face, what was lefts, was a Ghast, a demon from nightmares. with empty eyes and blinding pain, the infamous gaster was born.

* * *

When gran Torino called Nighteye to tell him about what All Might was doing, Mirai felt fear like he never did before. they have been tracking _**him** _for 12 years now, and All Might decided to fight the monster alone, they were searching for a corpse right now for goodness sake! he ran all the stairs to the top floor in the Might Tower and called a helicopter, 10 minutes later, they were flying above the surrounding jungles. they heard some tremors were heard recently, and they found it. a crater, the size of a city sat in the middle of the jungle, everything leveled as far as the eye could see. he instantly phoned it in, calling rescue squads to try and find the man. for all they know, All Might was supposed dead in this fight.

It took until 2:00 A.M. to find the man. he was unconscious and slightly bruised, but except that, he seemed just fine, maybe slightly less buff, but, he was completely fine, Nighteye could swear the man even looked healthier compared to before. watching the man, go; he slowly walked back to the old hero who had called him. his confusion was apparent as the old hero shrugged to the unasked question that hung in the air, Maybe All Might had the answers they need.

* * *

(Note that Izuku is 8 years old here and slightly shorter than Undertale Ghaster, he doesn't need to eat and sleep as his body had withered away, every once in a while he has to take souls to keep his 1/4 of a soul from getting completely depleted, so he fights bears and wolves in the jungle he is. he stumbled upon this underground facility from WWII as he was about to finish his 8th year.)

He woke up in a small bunker, remaining from the war before quirks appeared. it was classic in design, and it looked similar to school labs they had at school. (Military-grade chemistry equipment that belonged to 400 years ago is equivalent to school grade chemistry equipment of the day. if you wanna consider alchemy grade chemical equipment that belongs to pre-renaissance to be hard to find, I don't know how many centuries old are you.) the small flicker of the light above proved that he somehow, turned the backup generators back to life, so he started studying the structure. 

The engine was extremely simple, and it allowed him to easily upgrade it with the use of a few scrap metals, and the hole in his hand seemed to be able to generate heat. after working on the engine for who knows how long, Izuku finally got it running, and was satisfied as lights all around the facility started turning on. this place was the perfect place to take a refugee in after what he had gone through. 

Looking around, he noted that instead of a simple underground lab, he had stumbled upon a full underground facility, by the dust around, it was clear that this place hasn't been used for at least 3 centuries, and the structure was hazardous, so he decided to work on that, it would take some time, but the thought of having a place to call home, made his heart flutter, so he got to work, trying to strengthen the structure so he doesn't end up buried here. his base awaits him.

* * *

All Might waked up with a gasp, Looking around and failing to see the Ghast that was his savior, he kept shouting and screaming that they had to sedate him at first. the darkness was a welcome from the nightmare he saw before he fell unconscious. 

it took another week to get All Might out of his panic. whenever he woke up, he called out for a Ghast and tried to find him, the facility was about to write him off as mental when the man regained his bearing, a detective was called in for his debrief, and to learn more about this Ghast as well, it was common knowledge that the detective had a soft spot for children, so when a child goes missing at the same day All Might be fighting, he was suspicious, that concern was what led him to come to interrogate the wounded man.

"Hello sir, I'm Noamassa Tsukauchi, I am from the police force to get a verbal debrief of your recent battle and ask a few questions about this Ghast you've been talking about". and that was part of that can of worms he didn't want to talk about. a bit too All Mights left was what can only be described a ball of melted flesh and different body parts, all matching the medical records of the missing person Midoriya Izuku, a 5-year-old boy who had wandered to the jungle that fateful night.

the man sighed a little before he started." after my fight with the Villain, I had lost a lot of blood." Tsukauchi looked at him confused as what he said was true, All Might was healthy when they brought him in, only unconscious. so what was this information?

"In my fight with the villain, he shot a hole this big" he motions his hand to a small circle the size of his fist "Throuht my stomach, it narrowly missed my heart" again true.

"After I killed the man I was walking around in the jungle, trying to get to a city, and then I fell unconscious." he paused at this part, looking paler than he had been in this whole conversation.

"I am not exactly sure how it happened but, one moment I was completely knocked out, and then I felt like a part of me was being forcefully ripped out of me." he paused again gathering his thought. "a moment passed and there was nothing but darkness, a moment that seemed like an eternity. I don't know how long I was 'out' of it but a moment later, something replaced that missing feeling in my chest. My lung regrew, my stomach returned, my muscles bulked up, It was like I wasn't impaled at all." the man stopped, looking as white as a sheet that moment.

"But, as my muscles grew, I saw a boy, no taller than 3' 4" doubled over in agony, he was screaming in pain, and I couldn't even stand up. I saw what happened to the boy, his hair fell, his skin melted off, his eyes, he died." he paused a moment to look at Tsukauchi.

"The body was never found." the detective said grimly. "Neither was the villain nor was the child" he paused another moment. "the boy you saw was named Izuku Midoriya, he was known to have a quirk that allowed him to see colorful 'hearts' where people are. he described one of his classmates as a red heart and his teacher as a blue in his file. it was known to be a useless quirk since it didn't possess any practical applications, but as it seemed, it did something after all." he paused another moment, gathering his thoughts.

"When you came Here, Sir tried to use his quirk on you." and the hero looked at the Detective's expression. since the man didn't elaborate, it made the unease he felt increase tenfold. 

"What ... did he see detective?" he asked, not sure if he could trust his own voice.

"nothing." the detective said grimly, "he said that for the first time, he saw nothing as his quirk took effect, the possibilities were beyond his reach, so the future remains shrouded in mystery for now." and All Might breathed a sigh of relief because that could have been a much worse answer than what he was hoping, but now the question was how did his sidekicks quirk not work.

"Did he explain why his quirk wouldn't work on me?" the hero asked, unsure of the next course of action, there were many things to consider, as the Villains body wasn't found, the missing boy, this dilemma with his quirk, the damage the boy had taken, too many variables, too few equations.

"He explained that unlike a normal person, your soul has been tampered with. the future he saw, was static, a double image, of both your viewpoint and a jungle viewpoint, there were some bizarre pictures in his vision as he said, making the vision unreliable for use. he thinks it because he is watching a shared future between you and the boy, and not in the normal sense. we called Nedzu on the case and his opinion was that the boy who was capable of seeing 'souls' traded his healthy soul with your withering one, causing him to lose his own flesh and eyes and you regaining your health. the reason he provided for Nighteyes visions failing was that while the soul within you is yours by now, the boy's presence is still lurking in the depths of his soul. in a way, while saving you, he had also bonded a part of you, a vestige may I say to himself, and gave you his own vestige to you. there are yet many unknowns in this condition but until we get updated, we will go with this" the detective said, as he walked towards the door on the right.

"What would happen to the boy now?" All Might ask, not being able to let go of the dread that spread in his gut.

"We are trying to find him with deciphering Nighteyes visions, you can help us if you want later, I'll send you the details now."

and not a moment later, a ding came from Toshinori Yagi's phone. it was a 1-page file scan.

**Missing person in Musutafu**

**Name: Izuku Midoriya**

**Gender: Male**

**Quirk: Soul**

**Description: formerly possessed an eerily green hair and green iris, around 3' 4" and 5 years old, new info has been an individual who possesses no flesh and has white exoskeletal bones as his body, his skull posses two scars from both eye sockets, the left going towards the forehead when the right moves down to the mouth. his hands have holes within them, from people who have seen the individual, he was referred to as Ghast.**

**  
Case: Ghaster**

He couldn't shake the feeling that in this whole debacle, they were missing something important.


End file.
